1. Field of the invention
The present invention related to rail bogies adapted for connecting convertible rail highway semi-trailers and the like road vehicles together into trains for riding on railroad tracks.
2. Description of the prior art
Rail bogies, known in the trade as "Road-Railers", have fallen into near oblivion in the 1950s and have operated in relative obscurity until recently. But, they have since then been updated and are now knowing a strong revival, possibly due to less stringent regulations from transport authorities and, perhaps more so, due to a more aggressive marketing approach from the railway industry, desiring to recapture traffic lost long ago to highway carriers such as semi-trailers.
A brief history of a new rail bogie of this type is given in the September 1987 issue of Gazette International (page 605). It is a twin-axle bogie provided with a locking mechanism for joining the bogie and a semitrailer together. At the rail transfer site, the semitrailer is moved on the track and its body lifted by its own pneumatic suspension to allow the rail bogie to be rolled beneath the trailer body which is then lowered into position on the rail bogie, the trailer wheels being thereafter lifted further to clear the tracks safely. The back of the semi-trailer is also provided with a special coupler so that a trail of semi-trailers can be formed by having the back end of one trailer fitted to the rail bogie, in the manner aforesaid, and the front end of the next trailer hooked to the coupler at the back end of the preceding trailer. The coupling is efficient but the hooking procedure is time consuming and complex.
Another type of "RoadRailer" is described in the September 1987 issue of the magazine Traffic Management. In this case, the rail bogie is secured to the body of the trailer, between each pair of tire wheels. Once the trailer is moved on the railway track, the bogie is lowered to raise the trailer wheels sufficiently to clear the track safely. Several trailers may be end connected together to form a train. In this case, all trailers are equipped permanently with rails bogies which is an expensive method of road-rail transportation.